1. Field of the Invention
The invention relates generally to the field of loudspeakers employing a plurality of substantially rigid planar diaphragms, driven by cooperating coil and magnet units.
More specifically, the invention relates to a planar loudspeaker system having an elongated and substantially planar enclosure, configured to house tweeter, midrange, and a pair of woofer diaphragms in its median, longitudinal portion. A pair of quarter-wave woofer labyrinths extends throughout the remainder of the enclosure's volume. The labyrinths vent the woofer backwaves forwardly, toward the listener, through a pair of shared ports in the mid-frontal area of the enclosure.
The invention also relates to electro-magnetic drive units which apply a distributive driving force to the planar diaphragms, while presenting a distributive load to the drive amplifiers. Three versions or embodiments of the drive units are disclosed, each of which utilizes bar magnets, pole pieces, and thin encapsulated moving coils, all of elongated and symmetrical configuration, in accordance with the distributive drive and load design.